Pressure-controlled means for motor regulation



C. L. HOWSE PRESSURE CONTROLLED MEANS FOR MOTOR REGULATION FiledMax:112, 1922 g fav 7?ZZr HIIIWI w NIH ByMMMm LI i'mllml Patented Get.2?, i925.

utilise CURTIS I1. HOWSE, OF DETROIT, MICHIGAN, ASSIGNUR CRAIG BEGULATGRCUE/KEANE, ACORPO'EATIGN 076 DELAVTAEE.

PRESSURE-CONTROLLED WZEAN'S FOR IJIOTGR REGULATION.

Application filed March 2, 1922. Serial No. 540,650.

To all whom it may concern:

Be it known that I. Gnarls L. Howsn, a subject of the King of GreatBritain, residing at Detroit, in the county of Wayne and State ofMichigan, have invented certain new and useful Improvements in PressureControlled Means for Motor Regulation, of which the following is aspecification.

My invention relates to motor regulation, and more particularly to theregulation of an electric motor I consistently with variations of fluidpressure to which it is desired that speed of the motor should respond.Illustratively I have herein shown my invention as embodied in fashionto regulate an electric motor which drives the blast fan of an underfeedstoker, it being desirable in such an organization that, as boilerpressure rises, the motor shall drive the fan at lower speed, and asboiler pressure is lowered the motor shall drive the fan at higherspeed.

Among the particular objects of my invention are to provide a verypositive, eflicient and sensitive control, insuring power actuationofthe fan-motor rheostat consistently with boiler pressure variation, bya fluid motor which. itself is sensitively governed from the boilerpressure.

Other and further objects will become apparent to those skilled in theartfrom the following description taken in conjunction with theacompanying drawings wherein I have illustrated asingle embodiment of myinvention, mainly in diagrammatic form for purposes of clarity.

In said drawings Fig. 1 is a side elevation with parts broken awaydiagrammatically illustrating the embodiment of my invention in a fanmotor'regulator for an underfeed stoker; Fig. 2 is an enlarged view ofsome of the parts.

In the construction illustrated the boiler 10- is served by an underfeedstoker 11 to which air is variably supplied by fan 12 driven by electricmotor 13, which, for

rheostat device 14, shown as movable clock- Wise to cutin resistance andoppositely to cut out resistance; the movable contact ele-' mentbeingbiased by a Weight 15 on rheostat operating lever 16 to tend to moveclockwise. A chain 17 working on the sector surface 18 of said lever isoperated on by the piston of a fluid motor 19 to shift the rheostatcounterclockwise. This motor, in the form shown, comprises piston 20traveling in cylinder 21 into the upper end of which fluid undervpressure,preferably a small stream of wateris admitted through supplypipe 22, such supply being const'antly maintained. The wa ll of thecylinder is perforated'with numerous eduction ports 23 all communicatingwith a vertical passage 24 opening at its lower end to awaste-connection 25, this passage containing the vertically sliding,passage-closing valve 26 of cylindrical rod form which enters thepassage from the upper end which, by de pression, may progressively sealany num berof the lateral ports 23 beginning with the top. Manifestly,to whatever position below the level indicated in Fig. 2 this stoppingvalve may be depressed, water pressure above the piston will cause thepiston to travel down until it opens a lateral port 23 below theextremity of the valve 26 to permit constant escape of the fluid. G11the other hand, as valve 26 is raised, opening further ones of thevertical ports giving an excessive escape-opening for the fluid, theweight 15 will pull the piston upward until the condition isre-established ,wherefiuid-escape just takes care of fluidadmission.

In conjunction with such a power regulator-engine, accuratelycontrollable by the vertical shifting of'its valve stem 26, I providevalve-actuating means responsive to boiler-pressurev conditions, and,preferably in thesame mechanical train I provide electrically responsivemeans for abnormally operating the motor to permit return ofthe rheostatto full-resistance position in the event of rupture of the supply-linefor the motor. 7 v

From thesteam boiler 10 a pressure supply pipe 30 is led to the casingof a pressure-responsive devieesuch as a casing 31 for a diaphragm 32which acts, through a leverage system, to move the controlling valve 26of the fluid motor. The knifeedge lifting stem 33 of the diaphragm workson the multiplying lever 34 which is fulcrumed at 35 and suitablyweighted as at 36. This lever carries an extension lever 37 linked as at38 to the motor valve 26. By suitable proportioning of weights, thismechanism may be made very sensitive to pressure-changes allccting thediaphragm 32, and, all parts being very freely movable and practicallyincapable of sticking or developing substantial i lotion, the movementsof all parts are strong, smooth and powerful. Further, it will be noted,by so proportioning the port-spacing 23 ot the fluid motor for therheostat that movement from one port to another of the piston is justsuflicient to correspond with movement of a. rheostat arm from onecontact to the next, insurance ct regulation to the finest degree forwhich the rheostat is capacitated is afforded.

While, in normal operation, extension lever 37 may be regarded asrigiditied with lever 34, it is desirable that the extension lever beindeoendently operable fully to retract the valve 26 of the fluid motorshould the supply circuit for the electric motor be interrupted, thuspermitting the rheostat to go back to'tull-resistance position. Thus,extension lever 37 is tulcrumed as at 40 on lever 341- and a magnet a1is mounted on frame 42 carried by lever arm 3% a means for impartingindependent movement to the extension lever 37. This magnet nas suitable connection 43 with a suitable portion of the wiring M for theelectric motor 13, and while energized the magnet holds its heavyarmature 45 permanently raised. Upon interruption of current to themagnet, however, it drops its armature 4 5 which is united as by pin andslot connection 46 with the end of extension lever 37 so that thetelling weight of tie armature lifts the active end of the extensionlever and fully retracts the valve 26 for the fluid motor.

ln operation, assuming the parts to be in substantially the mid-positionshown, under normal steam pressure oi the boiler 10, rise in boilepressure. communicated to the diaphragm chamber 31 will cause thediaphragm to lift the lever 3% and its extension 37, so raising thesliding valve 26 for the fluid-motor and, by opening a higher one of theports 23, will permit the weight 15 of "he rheostat device to draw thepiston 20 pward. turning the contacts of the rheostat and cuttingresistance into circuit of the electric motor 13. Consequently the motorwill drive the blast fan 12 at a decreased speed. Should boiler pressuredrop, reverse operation will occur, the diaphragm 32 of thepressure-responsive device yielding to the weight 36 ot the lever arm34, the extension 37 whereof will force down the valve- .26 for thefluid motor, the piston of which will then seek a lower level, raisingthe rheostatweight and turning its contact arms counterclockwise to outout resistance, so speeding up the electric motor 13 and the fan 12.Should the motor circuit be broken, deenergization of magnet 41 willdrop the armature weight on the extension lever 37, rocking it on itsoivot a0, and so causing valve 26 to be retracted to maximum extent,permit ing the rheostat to go back to maXi- Ilium-resistance position.

l Yhile l have herein described in some detail a particular embodimentof my inven tion it will be seen that many changes in details ofconstruction and arrangement may be made without departure from thespirit of my invention within the scope of the appended claims.

1 claim:

1. The combination with a source of suprly of variable 'd-pressuro, anelectric otor to be speed; red according to varia- ,nfessure and meansfor t the uuid eluding a moral le part for long throw; of m ansconstantly urging said part in one direction; me is for exerting powerto move said partp'gi he opposite direction or hold said part stationaryagainst the opposing constant urge, as the case may be, said meanscomprising a piston, a cylinder therefor having provision for constantliquid supply to one end thereof, and long-throw valve means forpermitting liquid escape from the cylinder only when the piston is atdifferent distances from the cylinder end det imined by the movement ofsaid valve; pressure-responsive means connected with said source otvariable fluid pressure and having a diaphragm member displaceabledistances substantially acto varying small cordantly with pressurevariation acting thereon; and a multiplying lever 34 between saiddiaphragm member and the valve means for said cylinder to vary the position at which said valve means will permit liquid escape from thecylinder progressively throughout the range of piston travel, wherebythe piston may dwell at progressively different points in its range oftravel substantially accordantlv with the variations in fl l pro ire andthe movable member of the means for ctleeting motor-speed variation maydwell in accordantly regulated position.

2. The combination with a source of supply of *ariahle fluid pressure,an electric motor to be driven a variable speeds according to variationof said pressure, and aotor-speed-controlling means having a movablepart: means for moving said movable part to and retaining itin anyadjusted position. comprising a motor havii'ig a piston operativelyconnected with said movable part and having a long-throw valve tocontrol, in any of its positions of adjustment, the resultant positionof said piston; a pressure-respousivc device connected with the sourceof variable pressure; and operative connections between saidpressure-responsive device and said valve ineluding two members and anelectro-responsive device that is in the electric motor circuit, saidelectro-responsive device when energized rigidi'lying said member andwhen deenergized releasing said members for relative movement, therebyto free said valve for movement independently of the pressure-responsivedevice.

3. The combination with a source of supply of variable fluid-pressure, amotor to be driven at variable speeds according to variations of: saidpressure, and a speedcontrolling rheostat for said motor having amovable element, of means for governing the position of said elementincluding a piston connected with said arm, a hydraulic CURTIS L.HOVVSE.

